Date: Wed, 24 Jun 2009 14:48:34 +0500 From: rihad <rihad@mail.ru> To: Simun Mikecin <numisemis@yahoo.com> Cc: freebsd-fs@freebsd.org Subject: Re: Is it preferable to use the sync command? Message-ID: <4A41F672.9080900@mail.ru> In-Reply-To: <130804.21855.qm@web37303.mail.mud.yahoo.com> References: <4A41E073.70902@mail.ru> <130804.21855.qm@web37303.mail.mud.yahoo.com>
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Simun Mikecin wrote: > rihad wrote: >> Having experienced a FreeBSD 5.1 crash due to power failure (despite using a UPS) resulting in massive /etc corruption and data loss, in order to minimize future risks should I: >> 0) tweak (decrease) these default sysctls: >> kern.filedelay: 30 >> kern.dirdelay: 29 >> kern.metadelay: 28 >> 1) mount the root FS with soft-updates enabled (left as disabled in sysinstall by default due to known reasons) >> 2) setup a cron job calling /bin/sync every minute >> I somehow feel that turning soft-updates on would do the trick (it is not normally written to and has plenty of free space anyway). > > > Do you use ATA or SCSI? ATA. > Turning soft-updates on for SCSI should do the trick. But not for ATA? Why I'm asking: other partitions using soft-updates don't seem to have lost any data. > Since there is no support for gjournal and/or ZFS on 5.1, for ATA only real solution would be disabling write-cache (which degrades performance): "sysctl hw.ata.wc=0". > I think this is much easier to do remotely than turning soft-updates on :-) I'll still try both solutions, thanks.
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